If SpO2 declines below 90% the ventilator settings will be adapted according to the following protocol: First the FIO2 is increased to 80%. If this is insufficient FIO2 is increased to 100%. If this remains insufficient, continuous positive airway pressure (CPAP) [5 cm water (H2O) pressure] is applied to the non-ventilated lung. If this is still insufficient the surgeon will be asked to allow for temporary recruitment of the non-ventilated lung.